package com.example.fangwei.utilsapp.encrypt_utils;

import java.security.Key;
import java.util.Random;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;


/**
 * PBE安全编码组件
 * 
 * @author nosyman
 * @version 1.0
 * @since 1.0
 */
public abstract class EncrypPBE {

	/**
	 * 支持以下任意一种算法
	 * 
	 * <pre>
	 * PBEWithMD5AndDES 
	 * PBEWithMD5AndTripleDES 
	 * PBEWithSHA1AndDESede
	 * PBEWithSHA1AndRC2_40
	 * </pre>
	 */
	public static final String ALGORITHM = "PBEWITHMD5andDES";

	/**
	 * 盐初始化
	 * 
	 * @return
	 * @throws Exception
	 */
	public static byte[] initSalt() throws Exception {

		byte[] salt = new byte[8];

		Random random = new Random();

		random.nextBytes(salt);

		return salt;

	}

	/**
	 * 转换密钥<br>
	 * 
	 * @param password
	 * @return
	 * @throws Exception
	 */
	private static Key toKey(String password) throws Exception {

		PBEKeySpec keySpec = new PBEKeySpec(password.toCharArray());

		SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM);

		SecretKey secretKey = keyFactory.generateSecret(keySpec);

		return secretKey;

	}

	/**
	 * 加密
	 * 
	 * @param data
	 *            数据
	 * @param password
	 *            密码
	 * @param salt
	 *            盐
	 * @return
	 * @throws Exception
	 */
	public static byte[] encrypt(byte[] data, String password, byte[] salt)
			throws Exception {

		Key key = toKey(password);

		PBEParameterSpec paramSpec = new PBEParameterSpec(salt, 100);

		Cipher cipher = Cipher.getInstance(ALGORITHM);

		cipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);

		return cipher.doFinal(data);

	}

	/**
	 * 解密
	 * 
	 * @param data
	 *            数据
	 * @param password
	 *            密码
	 * @param salt
	 *            盐
	 * @return
	 * @throws Exception
	 */
	public static byte[] decrypt(byte[] data, String password, byte[] salt)
			throws Exception {

		Key key = toKey(password);

		PBEParameterSpec paramSpec = new PBEParameterSpec(salt, 100);

		Cipher cipher = Cipher.getInstance(ALGORITHM);

		cipher.init(Cipher.DECRYPT_MODE, key, paramSpec);

		return cipher.doFinal(data);

	}

	public static String encryptPBE(String src, String pwd, byte[] salt)
			throws Exception {

		byte[] input = src.getBytes();

		byte[] data = EncrypPBE.encrypt(input, pwd, salt);

		return Base64.encode(data);

	}

	public static String decryptPBE(String src, String pwd, byte[] salt)
			throws Exception {

		byte[] output = EncrypPBE.decrypt(Base64.decode(src), pwd, salt);

		return new String(output);

	}

}
